“Can this marriage be saved?” remains the central storyline as the House gets ready to vote on a farm bill next week.

The answer now looks to be a qualified “yes”: The union of crop subsidies and food stamps, created out of political convenience in the Nixon era, is on course to be preserved one final time.

But a no-fault divorce has a very good chance of being granted before the next farm bill is written near the end of the decade. After 40 years, more and more of the rural lawmakers who care most about the livelihood of farmers have decided they’re ready to dump their urban and suburban colleagues who care more about the nutrition of the poor.

The short-term survivability of the relationship has been in deep doubt for the past year. During that time, House GOP leaders put the entire farm bill into an indefinite timeout, knowing that putting it to a vote would mean defeat at the hands of an unusual coalition — conservative Republicans lamenting the bill wouldn’t cut domestic food aid deeply enough in these fiscally tough times, and liberal Democrats complaining that those same cuts would be far too harsh in these economically tough times.

The dynamic has now changed enough that Speaker John A. Boehner of Ohio has authorized next week’s debate and has promised that, despite voting against the current law as a budget-buster back in 2008, he’ll break with the speaker-rarely-votes tradition and cast his ballot for passage.

That’s a solid signal the legislation — which would reduce food stamp spending by 3 percent (or about $2 billion a year), in part through tougher eligibility rules — will pass with a comfortable margin.

Still, it probably won’t get a majority of votes from the majority caucus. Fiscal hawk groups such as Heritage Action say it’s still too expensive, and that view easily carries the day with the many Republicans in safe seats that mostly cover the countryside.

The dynamic is very different across the Capitol, where each senator represents some mix of city streets, suburban strip malls and country roads. That helps explain why 66 of them voted Monday to pass a bill that would trim food stamp spending in the next five years by only half of 1 percent, or $500 million annually.

Finding a middle ground that can sustain the balky and unusual geographic coalition — without causing that allegiance to get swamped by the more typical and partisan size-of-government disputes — will be a main challenge for the farm bill conferees. It may be their last hurrah.

One reason the regional alliance is nearing its end is that the balance of power and interests between the factions has gone out of whack. When the conservative Texas Democrat W.R. Poage started forging the coalition in 1969, when he was writing his first farm bill as House Agriculture chairman, the amount being spent on farm aid was nearly identical to the budget for food stamps. But the political support for boosting welfare was greater than for bolstering crop subsidies.

The rural guys were the suitors, in other words, because the urban guys had the more valuable trousseau.

Since the Great Recession started in 2008, right after the last farm bill was enacted, spending on food stamps has about doubled. This year, the government is spending about $80 billion to serve 1 in 7 Americans through what’s now called the Supplemental Nutrition Assistance Program. That price tag is four times as much as the annual grand total for commodity subsidies, agriculture research, crop insurance, land conservation, rural development and other programs that give the “farm bill” that name.

But for more and more in the House majority, their interest in managing the rural economy’s decline in a fiscally prudent manner far exceeds their interest in maintaining SNAP payments of $4.50 a day.

The rural guys, in other words, have decided their partnership with the urban guys is not worth the heartburn. And many GOP lawmakers from the suburbs, which hold the balance of power in American politics, have come to share that view.

This week, 14 House Republicans with mostly suburban constituencies joined nine GOP members from rural districts in petitioning Boehner to decouple the relationship. “Combining the reauthorization of federal agriculture programs and nutrition programs into one bill has resulted in a battle of competing interests, and it represents a major reason why reauthorization — and much-needed reform — of these programs have been unsuccessful thus far,” they wrote.

It’s very likely too late in the process to dissolve the marriage this year. No Republican on House Agriculture signed the letter, and Senate Agriculture Chairwoman Debbie Stabenow of Michigan has dismissed past talk of a breakup.

But the political pressure to curtail SNAP is not going away so long as it remains the only social welfare entitlement that’s subject to a re-examination twice a decade. By 2018, look for advocates of both farm and food aid to see the wisdom of going their separate ways and seeking happiness on their own.